The present invention relates generally to a system for transferring contact printing data from a sub-master tape to a blank tape, so-called slave tape or pancake tape. More specifically, the invention relates to a high-speed contact printing system including a feature for refining the waveform of control signals on the slave tape. In particular, the invention relates to a high-speed contact printing designed to duplicate video information in both Beta (.beta.) and VHS systems.
Contact printing techniques for duplication of video information are well-known. Contact printing can involve copying video information including control (CTL) signals from a pre-recorded sub-master tape to a slave tape at a relatively high speed.
Defects have been encountered in contact printing in that the control signals on the slave tape are susceptible to distortion. This is because the control signals cannot be sufficiently saturated during contact printing and because a signal level loss on the order of 6 dB/oct occurs during printing. This distortion of the control signal can easily cause the video tape recorder system to malfunction.
In order to resolve this defect in conventional contact printing, Japanese Patent First Publication (Tokkai) No. Showa 49-81018 discloses a feature for refining the control signals on the slave tape. The control signals are refined by means of the read head and record head. The read head reproduces the control signals immediately after being copied onto the slave tape. The reproduced control signals are sent to the recording head so that the control signal can be rewritten onto the corresponding section of the slave tape to ensure their saturation.
Therefore, the contact printing system disclosed in the Japanese Patent First Publication No. 49-81018 succeeds in refining the control signals and thereby preventing the video tape recorder systems from malfunctioning.
In addition, as is well known, in the field of video tape recorders, there are two different systems, namely, Beta (.beta.) systems and VHS systems. The .beta. system and VHS system employ different tape speeds and thus different pitches of the control signals on the video tape. For example, in NTSC system standard television monitors, the tape speeds in 2-hour mode, which in .beta. systems is the so-called .beta.II mode running at 1/2 the standard tape speed, and in standard mode in VHS system, are respectively 20.00 mm/sec. (.beta. system) and 33.35 mm/sec. (VHS system). Therefore, tape speed difference in 2-hour mode between .beta. and VHS systems is 13.35 mm/sec. per sec. In this case, the pitches of the control signals recorded on the mother tapes are respectively 0.6667 mm (.beta. system) and 1.11167 mm (VHS system). The difference between the pitches of the control signals in .beta. and VHS systems is thus substantial and cannot be ignored.
This substantial difference between the pitches of the control signals in .beta. and VHS systems requires different delay intervals between the read head and the record head. This prevents application of the control signal refining technique of Japanese Patent First Publication No. 49-81018 to both .beta. system video information and VHS system video information.